Description

Guanine nucleotide-binding proteins (G proteins) form a large family of signal-transducing molecules. They are found as heterotrimers made up of alpha, beta, and gamma subunits. Members of the G protein family have been characterized most extensively on the basis of the alpha subunit, which binds guanine nucleotide, is capable of hydrolyzing GTP, and interacts with specific receptor and effector molecules. The G protein family includes Gs (MIM 139320) and Gi, the stimulatory and inhibitory GTP-binding regulators of adenylate cyclase; Go, a protein abundant in brain (GNAO1; MIM 139311); and transducin-1 (GNAT1; MIM 139330) and transducin-2 (GNAT2; MIM 139340), proteins involved in phototransduction in retinal rods and cones, respectively (Sullivan et al., 1986 [PubMed 3092218]; Bray et al., 1987 [PubMed 3110783]). Suki et al. (1987) [PubMed 2440724] concluded that the human genome contains at least 3 nonallelic genes for alpha-i-type subunits of G protein; see, e.g, GNAI2 (MIM 139360), GNAI3 (MIM 139370), and GNAIH (MIM 139180).[supplied by OMIM]